a critical section as apparently required by both. I don't think either
belongs in the event timer front-ends but the callback should handle
this as necessary instead just like for example intr_event_handle()
does but this is how the other architectures currently handle it, either
explicitly or implicitly.
- Further rename and reword references to hardclock as this front-end no
longer has a notion of actually calling it.
a11f2eb6e8